Mine drainage from Ohio. The orange coating on the logs is ferrihydrite.
General
Category
Oxide minerals
Formula (repeating unit)
(Fe3+)2O3·0.5H2O
IMA symbol
Fhy[1]
Strunz classification
4.FE.35
Dana classification
04.03.02.02
Crystal system
Hexagonal
Crystal class
Dihexagonal pyramidal (6mm) H-M symbol: (6mm)
Space group
P63mc
Unit cell
a = 5.958, c = 8.965 [Å]; Z = 1
Identification
Formula mass
168.70 g/mol
Color
Dark brown, yellow-brown
Crystal habit
Aggregates, microscopic crystals
Streak
Yellow-brown
Diaphaneity
Opaque
Density
3.8 g/cm3
References
[2][3][4][5]
X-ray diffraction patterns for six-line (top) and two-line (bottom) ferrihydrite. Cu Kα radiation.
Ferrihydrite (Fh) is a widespread hydrous ferric oxyhydroxide mineral at the Earth's surface,[6][7] and a likely constituent in extraterrestrial materials.[8] It forms in several types of environments, from freshwater to marine systems, aquifers to hydrothermal hot springs and scales, soils, and areas affected by mining. It can be precipitated directly from oxygenated iron-rich aqueous solutions, or by bacteria either as a result of a metabolic activity or passive sorption of dissolved iron followed by nucleation reactions.[9] Ferrihydrite also occurs in the core of the ferritin protein from many living organisms, for the purpose of intra-cellular iron storage.[10][11]
Ferrihydrite (Fh) is a widespread hydrous ferric oxyhydroxide mineral at the Earth's surface, and a likely constituent in extraterrestrial materials. It...
coercivities for hematite have been achieved by dry-heating a two-line ferrihydrite precursor prepared from solution. Hematite exhibited temperature-dependent...
create ferrihydrite ions. These ferrihydrite ions are transported through ion channels to the tooth surface. The build-up of enough ferrihydrite ions leads...
and amorphous colloidal materials, including allophane, imogolite and ferrihydrite. In the World Reference Base for Soil Resources (WRB), andisols are known...
soil types. Soil magnetism increases when soil minerals goethite and ferrihydrite convert to maghemite on exposure to heat. Temperatures sufficient to...
alters into iddingsite (a combination of clay minerals, iron oxides and ferrihydrite) readily in the presence of water. Artificially increasing the weathering...
extract iron and aluminium from poorly-crystalline minerals (such as ferrihydrite), iron(II)-bearing minerals (such as magnetite) and organic matter.[page needed]...
oxygen and water, or damp, ultimately decomposes into iron oxyhydroxides (ferrihydrite, FeO(OH)) and sulfuric acid (H 2SO 4). This process is accelerated by...
control protein Family history FH, a gene that encodes the enzyme fumarase Ferrihydrite (Fh), a widespread hydrous ferric oxyhydroxide mineral McDonnell FH Phantom...
ferric hydroxide" or limonite. Much of this material may be the mineral ferrihydrite (Fe2O3 H2O). This dehydration or "aging" process has been found to be...
consists of a mixture of remnant olivine, clay minerals, iron oxides, and ferrihydrites. Debates over iddingsite's non-definite crystal structure caused it...
and amorphous colloidal materials, such as allophane, imogolite and ferrihydrite; high organic matter content, sometimes melanic epipedon; 0.7% of global...
with phosphate and hydroxide ions. The resulting particle is similar to ferrihydrite. Each ferritin complex can store about 4500 iron (Fe3+) ions. A human...
if they were not interacting. Nanoparticles of iron oxides, such as ferrihydrite (nominally FeOOH), often cluster and interact magnetically. These interactions...
which also occurs naturally as the mineral magnetite; Iron ochre or ferrihydrite: 338 — Fe2O3·0.5H2O, is a widespread hydrous ferric oxyhydroxide mineral...
Andosols are given the Silandic qualifier. In both cases, they contain many ferrihydrite and have a bulk density ≤ 0.9 kg/dm3. Silandic Andosols are very fertile...
should be isolatable from water. Moreover, in 2007, the structure of ferrihydrite was determined and shown to be built of iron Keggin ions. This further...
transformation of certain iron oxyhydroxide minerals, such as lepidocrocite and ferrihydrite. It occurs as widespread brown or yellow pigment in terrestrial sediments...
rocks to produce iron an aluminum hydrous oxide clay soils. Hydrate Ferrihydrite Weiser, H. B. (1920). "Hydrous Oxides. I". The Journal of Physical Chemistry...
shell in the Fe3+ oxidation state as water-insoluble compounds such as ferrihydrite and magnetite. Ferritin is able to store electrons for at least several...
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